Process for the manufacture of yeast from molasses.



GUSTAV ROTH, or OLM'U'JSZ, AUSTRIA-HUNGARY.

PROCESS FOR THE MANUFACTURE OF YEAST MOLASSES.

No Drawing.

To all whom it may concern:

Be it known that I, GUSTAV Born, a subject of the Emperor ofAustria-Hungary,

- residing at Olmiitz, Moravia, Austria-Hungary, have invented new anduseful Improvements in Processes for the Manufacture of Yeast fromMolasses, of which the following is a specification.

The treatment of molasses for the manufacture of yeast, offers as iswell known certain difficulties, more particularly in hot weather.Moreover, the results are not uniform. Now and then the yeast is ofexcellent quality but frequently it has a bad color and is frequentlyinfected. Moreover it is known that molasses of different origins are byno means of equal value for the manufacture of yeast by the processeshitherto used.

The present invention solves the problem of manufacturing yeast frommolasses in a uniform and reliable manner, with or without the aid ofthe lactic acid process.

The usual method heretofore employed for obtaining wort by usingexclusively mineral acids (that is to say, without the production oflactic acid by a bacterial process) takes place asis well known in thefollowing manner: The molasses is first diluted with water, neutralizedwith mineral acid (sulfuric acid or hydrochloric acid) or, morecorrectly speaking, mixed with a slight excess of acid, until a degreeof acidity of about 1.5 per 100 cubic centimeters of mixture isobtained, and thereupon boiled by steam, until the molasses when cooled,sep arates a dark mud and becomes sufliciently clear and contains thewhole "of the sugar contents in the form of dextrose. After settling,the entire mass of clear solution is run into the preliminary mashingtun, brought to the desired concentration and acidity, mixed with maltand then introduced into the clarifying vats.

When employing simultaneously the lactic acid production by thebacterial method, the usual processes for obtaining the wort, are

' as follows: The molasses which has been clarified in the abovedescribed manner by acidifying with mineral acids and by boiling areleft to acidify in the preliminary mashing vat after the soaking of themalt therein. (The soaking ofthe malt can however be Specification ofLetters Patent.

Patented Feb. 1, 1916.

Application filed March 28, 1914. Serial No. 827,816.

eflt'ected also after the acidifying process.)

-For starting the acidifying, lactic acid bacteria are cultivated bymeans of a small amount of a setting in mash prepared from grist ofdried malt and ground rye or there is added a corresponding quantity ofa suitably acidified principal mash (obtained from a previousoperation). When the desired degree of acidity is reached, the mash isheated to 75 C. for the purpose of sterilizing, and then transferredinto the clarifying vat.

After long experiments, I have found that a solution of molasses,diluted in the usual manner, acidified and drawn off clear afterboiling, still contains impurities. These impurities separate in a veryfine suspension when the molasses is diluted a second time, mixed withacid and strongly stirred or aerated. As scientific explanation for thisprecipitation, it appears probable that certain of the colloidalmattersin the molasses, by the action of this second dilution andacidification, together with the stirring or aeration, are convertedfrom the sol .condition into the gel condition. This conversion makesthe said matters readily separable from the molasses solution. If thesolution of molasses is deprived of the separated finely dividedimpurities by suitable filtration, it is a bright clear liquid, bytreating which a yeast of excellent and uniform quality is alwaysobtained. Another advantage of this process consists in the fact thatthe solution of molasses can be brought directly into the fermenting tunand mixed therein with clear extracts introducing nitrogen-containingingredients into the wort.

The further purification of the already cleared solution of molasses,introduced ac cording to this invention between the old which is stillmore essential, imports the removal of a dangerous accidental factor.The latter consists in the fact that the malt in the clarifyingprocesses hitherto used, holds back 7 sometimes more and sometimes less,fine impurities contained in the apparently perfectlycleardnolasseswhich impurities, as has "been proved by exactexperiments, endanger to a high degree the good quality of the yeast,

and therefore are of the greatest importance several hours to acidifyand is finall brought into the fermenting vat. The clarifying process istherefore done away with also in this case. Of course, the process couldalso be carried out so that a portion of I the lactic acid, or even thewhole quantity,

would be produced before the filtration of the molasses.

As examples of carrying out the process the following may be mentioned:The molasses is diluted to about 35 Balling, and acidified with sulfuricacid to about 4: cubic centimeters per 100 cubic'centimeters of mixture,whereupon, according to their nature, they are boiled for several hoursin the known manner and then left to stand until clarified. The clearsolution of molasses drawn oil, is then further diluted to about.

20 Bailing, and acidified Wit'HfSlllfllfiC acid to about 6-10 cub.centimeters per 100 cubic centimeters of mixture; The solution is thenpreferably aerated for some time. The impurities then separate in astate of an extraordinarily fine division, and must be removedcompletely' by careful filtration. When mineral acidis exclusively used,the molasses thus purified is brought directly into the fermenting vat,and mixed with clear nitrogen-containing extracts, distillers wash,nourishing salts or the like in order to be pitched with yeast. Whenlactic acid fermentation is simultaneously used, the purified brightclear solution of molasses is mixed in an acidifying vat with clearnitrogen-containing extracts, distillers wash and nourishing salts,diluted to about 14 Balling and after the addition of a culture oflactic acid bacteria in the form of clear wort at 50-60 left to standfor the purpose of acidifying. After the desired degree of acidity isreached, the solution is fermented by the addition of yeast as above.

To make the process successful, it is essential to carry out thefiltration properly by which the molasses is deprived of the impuritiesseparated asa fine'suspension. It has been found advantageous to carryout the filtration without pressure and to' employ a large filteringsurface.

The impurities separating in the form of a suspension, are so finelydivided that in the case of a filtration with pressure they would becarried through the finest filtering material. In that way, however, theefii-. -'ciency' of the process would be reduced. or

the filtration according to this inventiontaking place slowly andwithout pressure. In order to compensate for the slow working due tofiltration without pressure, it is advisable to use large filteringsurfaces.

I claim:

1. In the process of producing yeast from molasses, the improvement inthe preparation ofa clear Wort which comprises diluting the molasses inthe usual manner, acidulating the same, boiling the diluted andacidulated molasses, and drawing off the clear liquid, further dilutingand. acidulating the liquid to a suificient extent to cause theseparation of finely divided suspended matter, and thereafter separatingthe clear liquid from the said suspended matter.

2. In the process of producing yeast from molasses, the improvement. inthe preparation of a clear wort which comprises diluting the molasses inthe usual manner, acidulating the same, boiling the diluted andacidulated molasses, and drawing ofi" the clear liquid, further dilutingand acidulating the liquid to a sufiicient extent to cause theseparation of finely divided suspended matter, and thereafter separatingthe clear liquid from the said suspended matter, by filtration atatmospheric pressure, .over a large filtering surface.

3. In the process of producing yeast from molasses, the improvement inthe preparation of a clear wort which comprises diluting the molasses inthe'usual manner, acidulating the same, boiling the diluted andacidulated molasses, and drawing off the clear liquid, further dilutingand acidulat- .ing the liquid to a suflicient extent to cause theseparation of finely divided suspended matter, stirring or aerating theliquid and thereafter separating the clear liquid from the saidsuspended matter, then adding a clear nitrogenous extract andfermenting.

4. In the process of producing yeast'from molasses, the improvement inthe preparation of a clear wort which comprises diluting the molasses inthe usual manner, acidulating the same, boiling the diluted andacidulated molasses, and drawing off the clear liquid, further dilutingand acidulating the liquid to'a sufficient extent to cause. theseparation of finely divided suspended matter, then stirring or aeratingthe liquid and thereafter separating the clear liquid from the saidsuspended matter, then mixing the liquid with a clear nitrogenousextract, then adding lactic aeld lmt'ttl'lil in the form .of clear wort.leaving the solution to acidity.

and then fermenting.

A process of producing: yeast from molasses which comprises thesuccessive steps of (1) diluting, (2) acidifying. (1-3) boiling, (4)drawing oif the clear liquor (5) further diluting, (6) furtheracidifying sufficiently to cause a precipitation of finely dividedmatter (7) stirring or aerating, (8) removal of the finely dividedprecipitated matter, and thereafter (9) fermenting.

. GUSTAV ROTH.

\Vitnesses Jos srli: E. STADLER,

KARL GRUBER.

